The effectiveness of management of such contexts lies essentially in an assessment of the situation that is at the same time rapid, reliable and permanent. This involves gathering all the data necessary to characterize it in terms of criticalness (what is the level of seriousness?), of space (what is the extent of the crisis?) and of time (how will the situation evolve?). In centralized crisis management, which is the most frequent case, all of these data must then be conveyed to the central station coordinating the actions on the ground.
The nature of the data to be acquired to construct and keep up-to-date a good representation of the situation depends on the nature of the crisis in question: visual observation, direct observation when possible without risk or else observation by means of remote cameras, clearly constitutes a preferred source of information. The means used must however be compatible with the context (perception of day and/or night, need for multiple viewpoints, presence of contamination, discretion, etc.) and are not necessarily sufficient to grasp all the dimensions of the crisis.
Therefore, in addition to solely the direct or remote view, dedicated sensors are often required to enhance the knowledge of the situation; it is possible in particular to consider acoustic sensors (microphones), nuclear, chemical, biological or radiological contamination sensors, sensors of temperature and for detecting movements and even GPS location modules.
There is therefore a serious need for adaptability and modularity in the perception equipment to be used in order to gather the most complete information possible.
The capability to gather simultaneously data over the whole area concerned, through a more or less dense network of complementary sensors, constitutes another factor in the success of crisis management. It is therefore necessary to have means allowing an appropriate positioning and a rapid deployment of these multiple items of equipment, which will allow a permanence (endurance) of maximum operation.
The quality and richness of the data delivered by the majority of sensors in question depend greatly on their placement in the field. Positioning high up makes it possible to extend the range of perception, in particular for the observation sensors (cameras) which constitute one of the main sources of information, and makes it possible to avoid obstacles specific to the urban environment, a context of preferred application of the present invention.
Finally, the gathering of information spread over the crisis area must be accompanied by appropriate communication means making it possible to convey the data to the centralized management station. The existing infrastructures (telephone networks, internet network, etc.) can satisfy a portion of the need, for example between a “sensor network communication node” and the centralized management station; on the other hand, it is still necessary to put in place the individual (radio) transmissions between the sensors and this “communication node” by seeking to avoid as much as possible the radio transmission problems specific to the urban environment (concealing elements and masking elements, interfering reflections, etc.). A capability for rapid positioning of antennas and/or of communication relays on high points of the urban environment is necessary to the credibility of a distributed information gathering apparatus, with accelerated deployment. This capability may be combined with the capability already allowing the various sensors to be deployed high up.
A first solution consists in manually installing the sensors in question. But manual installation of the sensors does not make it possible to easily take advantage of positioning high up. The use of ladders, lift trucks or of any other equivalent means requires considerable logistics; the necessary means are not always immediately available and their use always requires considerable delays incompatible with the speed of reaction usually sought in a crisis situation. Moreover, the discretion required by certain uses (police, military) also suffers when use is made of heavy deployment means.